Microelectronic devices, such as integrated circuit chips, are widely used in consumer and commercial applications. As the integration density of microelectronic devices continues to increase, it may become increasingly difficult to provide a sufficient quantity of high performance interconnects that connect the microelectronic device to a next level package. The interconnects may be used to transfer signals and/or power. Accordingly, the interconnect density and/or performance may be a limiting factor in the further integration of microelectronic devices.
It is known to provide alternating current (AC)-coupled interconnects for microelectronic devices. These AC-coupled interconnects may be characterized by the absence of a direct current (DC) connection. This technique is known as “proximity communication”. The technique replaces wired communications between chips with inductive or capacitive interconnect between spaced apart inductive or capacitive elements to provide interconnects. Compared with traditional area ball bonding, proximity communication techniques offer greater density (in terms of connection number/pin number) than ball bonding and increases in communication speed between chips in an electronic system.
With specific reference to capacitive proximity communication interconnects, increasing the capacitance of the proximity communication connections improves the transmission channel. Various approaches are proposed in the prior art to increasing the capacitance of this connection. One such approach involves thinning the substrate of the chips. This approach, however, is difficult to control and costly. Moreover, the roughened substrate surface can lead to capacitance variations from site to site.
A second approach to increasing capacitance of the interconnect is to increase the area of each communication site. This approach is, of course, area hungry and costly.